Since its founding in 2002, Nanosolar has raised a lot of money – half a billion dollars to date – and made a lot of noise about upending the solar industry, but the Silicon Valley start-up has been a bit vague on specifics about why it’s the next big green thing.

On Wednesday, Nanosolar pulled back the curtain on its thin-film photovoltaic cell technology — which it claims is more efficient and less expensive than that of industry leader First Solar — and announced that it has secured $4.1 billion in orders for its solar panels.

The typical Nanosolar farm will be between 2 and 20 megawatts in size, Mr. Roscheisen said in an e-mail message from Germany, where he was attending the opening of Nanosolar’s new factory near Berlin. “This is a sweet spot in terms of ease of permitting and distributed deployment without having to tax the transmission infrastructure.”

When Intel announced this week that it was spinning off a stealth in-house startup called SpectraWatt to develop solar cells, it appeared the chip giant was just the latest old-line Silicon Valley tech firm bitten by the green bug.

But it’s not just now jumping on the enviro-biz bandwagon – Intel’s solar efforts have been quietly under development since 2004. That’s when Andrew Wilson, an 11-year Intel (INTC) veteran, was chatting with a colleague while waiting for a conference call to begin. “We were shooting the breeze and I mentioned that I had replaced all the light bulbs in my house with compact fluorescent lights and my utility bill had come down by a third,” says Wilson, SpectraWatt’s CEO. “And he said, `Hey, did you know that solar cells are made of silicon?’ ”

“We started talking about what a business plan would look like, because if something is made out of silicon then Intel should be taking advantage of that market,” Wilson told Fortune. A year later, Wilson and his colleagues had developed a marketing plan and secured funding from Intel’s new-business incubator to develop a business strategy and hone its technology. (It’s no coincidence that the nascent solar industry is populated by computer industry veterans from companies that put the silicon in Silicon Valley.)

When it comes to cutting-edge solar technology, silicon-based cells are considered a bit old-school. Silicon is currently in short supply and the resulting high prices have led venture capitalists to invest hundreds of millions of dollars in thin-film solar startups that promise to dramatically lower the cost of solar by printing or otherwise applying non-silicon solar cells to glass or flexible materials that can be integrated into walls, windows and other building materials. While thin-film solar is less efficient at converting sunlight into electricity, the expectation is that it can be produced much more cheaply than conventional cells.

But thin-film solar is still largely an early-stage technology and silicon-based cells will continue to be the big market for the near-future. So the question is, how does Intel compete with established players like SunPower, China’s Suntech (STP) and Germany’s Q-Cells as solar cells become a commodity? Intel controls some 80 to 90 percent of the worldwide chip market but it’s unlikely that it – or any other player – will replicate that experience in solar cells.

Wilson’s view is that it’s early days for the solar market and that SpectraWatt’s ace in the hole is Intel’s global manufacturing experience and history of technological innovation. “The solar industry today looks like the microelectronics industry in the late ‘70s – there’s very few standards and no one is manufacturing at scale,” says Wilson. “It’s all about manufacturing processes and material sciences that will lead to fundamental breakthroughs. The product is vastly simpler than a microprocessor but the fundamental nature of a solar cell isn’t all that different. When you think of what it takes to manufacture globally and manage supply chains, that’s Intel’s core competence.”

There certainly is room for more players, given that solar was a $30 billion market in 2007 and is expected to continue to grow at a clip of 30 to 40 percent in the coming years.

Wilson says SpectraWatt has secured silicon supplies and is developing technology that will give it a competitive edge. He’s keeping mum about the details of that technology for now. “We do believe we will have a technological advantage when we get what we’re doing in the lab to manufacturing,” Wilson says.

The company is set to begin building its manufacturing facility in Oregon later this year, with production to begin in mid-2009.

SpectraWatt launches with a $50 million investment lead by Intel Capital, the company’s investing arm. Other investors include Goldman Sachs (GS), PCG Clean Energy and Technology Fund, and German solar giant Solon. (As Green Wombat has written, Solon has invested in an array of solar startups in the United States, including Sungevity and thin-film solar company Global Solar.)

About Green Wombat

Green Wombat is written by
Todd Woody, a veteran environmental journalist based in California who writes for The New York Times, the Los Angeles Times, Grist and Yale e360. He's one of the few people on the planet who have held a northern hairy-nosed wombat in the wild.

Todd formerly was a senior editor at Fortune magazine, an assistant managing editor at Business 2.0 magazine and the business editor of the San Jose Mercury News.